The goal of this project is to identify genetic loci responsible, at least in part, for phenotypic variation in traits related to obesity. As part of an ongoing study of traits related to obesity in the Old-Order Amish, seven two- and three-generation families were assessed for twenty-one obesity related traits and genotyped. Model independent linkage analysis identified candidate regions for many of the traits, e.g. linkage to chromosomes 1,5, 7, 8, and 11 for body mass index (BMI) and %BMI (BMI adjusted for age and sex). The genotyping of markers flanking candidate regions allowed for further linkage analysis and tests of association to further define the candidate regions, e.g. linkage of BMI to a region flanked by markers D7S1804 and D7S3070. The results for BMI were presented as a platform talk at the 2002 American Society of Human Genetics (ASHG) conference and published in the American Journal of Medical Genetics. Results from an association study of a GNB3 variant (C825T) and blood pressure has been submitted. In addition, evidence for genetic linkage for several biochemical traits related to obesity (e.g., blood pressure, glucose, insulin, and thyroid hormones) are being presented at the 2003 Annual Meeting of the American Society of Human Genetics meeting and are being submitted for publication. A manuscript detailing linkage analysis of anthropometric measures is also in preparation.